A Quantum Arrow of Time

Is quantum mechanics messing with your memory? For all we know we may live in a world in which windows un-break and cold cups of coffee spontaneously heat up, we just don’t remember. The explanation is quantum entanglement.

A physicist has claimed that glass can un-break – but quantum entanglement prevents our brains from recording the event.

Imagine if a cold cup of coffee spontaneously heated up as you watched. Or a cracked pane of glass suddenly un-broke. According to physicist Lorenzo Maccone at the Massachusetts Institute of Technology, you see things like this all the time – you just don’t remember.

We have a statistical law that describes these everyday phenomena called the Second Law of Thermodynamics. This law tells us that the “entropy” or degree of disorder of a closed system never decreases. Roughly speaking, a process in which entropy increases is one where the system becomes increasingly disordered. Windows break, thereby increasing disorder, but they will not spontaneously unbreak. Gases will disperse but not spontaneously compress.

Lorenzo Maccone argues that quantum mechanics dictates that if anyone does observe an entropy-decreasing event, their memories of the event “will have been erased by necessity”.

Maccone doesn’t mean that your memories will never form in the first place. “What I’m pointing out is that memories are formed and then are subsequently erased.”

When you observe any system, according to Maccone, you enter into a “quantum entanglement” with it. That is, you and the system are entangled and cannot properly be described separately.

The entanglement, Maccone says, is between your memory and the system. When you disentangle, “the disentangling operation will erase this entanglement, namely the observer’s memory”.

But he cannot prove that entropy-decreasing events occur. Rather, he shows that if they do, we won’t remember them.

Huw Price, head of the Centre for Time at the University of Sydney, thinks Maccone is simply trading one mystery for another.

“The proposal to explain the thermodynamic arrow in terms of the [quantum] effects of observers has an obvious flaw,” he says. “It doesn’t explain why all observers have the same orientation in time … Why don’t some observers remember what we call the future, and accumulate information towards what we call the past?”

Real-world events always proceed in the direction of increasing entropy. The reason we never see events that reduce entropy is that they cannot leave behind any evidence of having happened, according to a new theory.

The mathematical laws of physics work just as well for events going forward or going backward in time. Yet in the real world, hot coffee never unmixes itself from cold milk.

When viewed in quantum terms, events that increase the entropy of the Universe leave records of themselves in their environment. The researcher proposes that events that go “backward,” reducing entropy, cannot leave any trace of having occurred, which is equivalent to not happening.

Lonely planet

The idea that intelligent life on Earth is a cosmic oddity strikes many as unwarranted terrestrial exceptionalism. There are some 300 billion stars in the Milky Way galaxy besides the sun and, by the latest estimates published earlier this month in Nature, each has, on average, at least one planet orbiting it.Even if only a tiny fraction could, in principle, sustain life, and only a tiny fraction of those actually do, that should still leave an awful lot of neighbours. Some of them would surely have called on man by now.

Why, then, haven’t they? The question, first posed explicitly in 1950 by Enrico Fermi, an Italian-American physicist, has elicited a plethora of responses. Perhaps civilisations just do not feel like chatting, or fear that humans could not handle it, or invariably destroy themselves before reaching the technological threshold at which interstellar communications become feasible? Alongside such inherently untestable proposals, however, are some more tractable ones. One is that although civilisations exist, they are few and slow to expand—and so have yet to reach Earth. Another is that galaxy is teeming with intelligent lifeforms, but they are unevenly distributed; Earth just happens to find itself in a bare patch.

Scientists calculated that any galactic empire would have spread outwards from its home planet at about 0.25% of the speed of light. The result is that after 50m years it would extend over 130,000 light years, with zealous colonisers moving in a relatively uniform cloud and more reticent ones protruding from a central blob. Since the Milky Way is estimated to be 100,000-120,000 light years across, outposts would be sprinkled throughout the galaxy, even if the home planet were, like Earth, located on the periphery.

And though 50m years may sound a lot, if intelligent life did evolve more than once, it could easily have done so billions of years before this happened on Earth. All this suggests that humans really do have the Milky Way to themselves. Either that or the neighbours are a particularly timid bunch.

The Way of the World, by Nicolas Bouvier

Nicolas Bouvier was Switzerland’s answer to Jack Kerouac.

Reviewers tend to band about superlatives with casual abandon these days, declaring second-rate works to be masterpieces, hyping the ordinary. Perhaps these easy eulogies are a response to the sheer volume of new material, as if quantity must inevitably lead to more quality. Or maybe it’s a surrender to the celebrity culture, where notoriety is valued above intrinsic worth. But whatever the cause, this disservice to readers – though not to publishers’ publicity departments – diminishes the power of language, lowers expectations of excellence and makes it very difficult to draw attention to a truly exquisite travel book of exhilarating imagination, especially when it’s over 40 years old.

As a child Bouvier’s reading of RL Stevenson, Jules Verne and Jack London made him impatient for the world. He recalled at the age of eight “tracing the course of the Yukon with my thumbnail in the butter on my toast”. His father encouraged him to travel and in 1953, without waiting for the result of his degree, he left bourgeois Switzerland with no intention of returning. In a small, slow Fiat, he and his friend Thierry Vernet – whose stark illustrations are reproduced in this handsome Eland edition – travelled across Europe and Asia over nineteen unforgettable months, pausing in Belgrade, Istanbul, Tabriz and Quetta to paint, write and wait tables, taking longer than Marco Polo – as Bouvier proudly pointed out – to reach Japan.

Along the road no sensational, headline-grabbing event befell them. They were not attacked by Baluch bandits or held hostage by an Afghan warlord. They did not climb the Hindu Kush in search of lost treasure. Instead they journeyed humbly, honestly and in near-poverty, failing to get jobs in Turkey, dossing down in a provincial prison in Iran, teaching French in Tehran to raise funds, and finding sanctuary in Quetta in a bar run by a distracted, kindly ex-Welsh Guards officer with “an air of something both luminous and shattered”.

Ten years in the writing, The Way of the World is a masterpiece which elevates the mundane to the memorable and captures the thrill of two passionate and curious young men discovering both the world and themselves. Racy and meditative, romantic and realistic, the book is as brilliant as Patrick Leigh Fermor’s A Time of Gifts, but with its erudition more lightly worn and as alive as Kerouac’s On the Road, though without a whisper of self-aggrandisement.

Through that distance Bouvier enables us to rise above faddish celebrity and the sterility of domestic despair, to remember that the world is a beautiful place and to rejoice in humanity. He writes, “Travelling outgrows its motives. It soon proves sufficient in itself. You think you are making a trip, but soon it is making you – or unmaking you.” If you read any travel book this year – or indeed in the next forty years – this should be it.